Check out the FormattingRules and then play in the SandBox. You can learn the basics of WikkaWiki by taking one of the visual tours. Some of the features on this server (like custom skins) can be tested by registered users only, so you are invited to register your free account.

Several user-contributed extensions are also available for downloading. Wikka is an open source project and welcomes contributions from new developers. If you intend to contribute code to Wikka, please read the WelcomeDeveloper page to get started.